The MLS has grown so much that these moves don’t have a significant effect.
The Martins move isn’t particularly surprising considering he’s played for a number of teams.(I don’t agree that he’s off chasing his next payday). The league continues to attract well-known foreign talent so there won’t be too much worry there. The Miazga move was surprising as well but there will be more young American talent to come through so no biggie there either.